CA1072880A - Thiophenes useful in the control of certain arthropods - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The substituted thiophene, 2,3,5-triphenylthiophene, is effective in controlling insects and mites.

Description

This invention relates to a method o~ controlling c~rtain arthropods, using the substituted thiophene,

2,3,5-triphenylthiophene as well as to a composition useful in such method.
Arthropods which are controlled by the method o~
the invention include acarids, particularly plant-feeding mite and mites and tickswhich af~lict man and animals, as well as insect pestsJ
Plant-feeding mites produce enormous losses to 10 agricull;ural corps in a world plagued by constant shortages o~ ~ood Crops such as al~al~a, apples, corn, cotton, grapes, oranges, potatoes, sorghum, peanuts and many others may be completely devastated by these tiny pests.
In additlon, various ~Ipecies have become so special-15 lized in structure and habit t;hat they must subslst on the bodies o~ man and animals. Few domesticated or wlld animals are immune to their at;tack. Mites are expert at torment~ng their host. There is probably no creature in existence which can cause ~ore torMent ~or its size than 20 a "chigger" can by burrowing beneath the skln o~ man~
; Other species such as itch and mange mites eause serious skin diseases in ~nimals such as dogs, cats, rabbits~ horses, cattle and pigs.
Ticks and some species of mites suck the blood o~ man ~nd animals. Besides the irritation involved~ a multitude of anima~ diseases may be transmitted by this method o~ food procurement Dread diseases such as Rocky Mountaln spotted f`evcr, relapsln~ ~ever and tularemia are tran~mltted by the bltes o~ ticks~ -During the last thirty years, numerous chemicals .:

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have been utilized in protecting both man and man's food and fiber against injury from mites and ticks, as well as insects. There is a continuing need for novel, effective and safe chemicals to accomplish this task. -In accordance with the invention it has now been found that the substituted thiophene 2,3,5-triphenylthiophene is useful in the control of arthropods.
The invention is practiced by applying to a locus, subject to a-ttack by certain arthropods, viz., acarids or insects, an effective amount, viz., an acaricidal or insecticidal amount, of the chemical 2,3,5-triphenylthiophene.
Frequently the locus is either plant life, for example such crops as alfalfa, apples, corn, cotton, grapes, oranges, potatoes, sorghum, peanuts, etc., or animal life, including man.
The chemical may be applied alone ~r with a carrier, which may enhance the effectiveness of the active agent or facilitate handling, to loci to be protected lagainst mites or the like, for example as dusts when admixed with or absorbed on powdered solid carriers, such as the various mineral silicates, e.g., mica, talc, pyrophillite and clays, or as liquids or spra~s when in a liquid carrier, as in solution in a suitable solvent, ;
such as acetone, benzene or kerosene, or dispersed in a suitable nonsolvent medium, for example, water. In protecting plants (the term including plant parts) which are subject to attack by these pests, the chemical employed in the present invention is preferably applied as an aqueous emulsion contain-ing a surface-active dispersing agent, which may be an anionic, nonionic or cationic surface-active agent. Such surface-active agents are well known and reference is made to Canadian Patent No. 512,908 for detailed examples of the same.
The chemical may be mixed with such surface-active dispersing - 2 - ;

. . . , ~ , agents, with or without an organic solvent, as acaricidal concentrates for subsequent addition of water to make aqueous suspensions of the chemical of the desired concentration. The chemical may be admixed with powdered solid carriers, such as mineral silicates, together with a surface-active dispersing agent so that a wettable powder may be obtained, which may be applied directly to loci to be protected against mites or the like, or which may be shaken up with water to form a suspension of the chemical (and powdered solid carrier) in water for application in that form. The chemical may be applied to loci to be protected against mites or insects by the aerosol method.
Solutions for the aerosol treatment may be prepared by dissolving the chemical directly in the aerosol carrier which is liquid under pressure but which is a gas at ordinary temperature (e.g., 20C.) and atmospheric pressure, or the aerosol solution may be prepared by first dissolving the chemical in a less volatile solvent and then admixing such solution with the highly volatile liquid aerosol carrier. ~'he chemical may be used admixad with carriers that are active of themselves, for example, other insecticides, acaricides, fungicides, or bactericides.
Practical formulations ordinarily contain from 1 to 95~ active ingredient. Spray dilutions may range from a few parts per million to undiluted concentrate applied by ultra low volume techniques. The concentration of chemical per acre -~
would vary depending upon many factors, but normally range from 0.1 to 10 pounds.
In one aspect, the invention is directed to new compositions useful in the control of certain arthropods, comprising the desigr.ated substituted thiophene chemical, in acaricidally or insecticidally effective amount, in combination with a carrier therefor.

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The following examples will serve to illustrate the practice ~f the invention in more detail.
Example 1 Mite Contact Test Cotton, Gossypium hirsutum L. - variety Stoneville-213, in the second primary leaf stage, grown in twelve ounce cups under greenhouse conditions at 70-75F, was used in this test. One plant (two primary leaves) in one pot was used for each replicate; two replicates were used. A one-inch diameter circle of tree tanglefoot, a sticky, non-toxic preparation, was used to confine the mites to the upper leaf surfaces.
Approximately twenty-five adult two-spotted spider mites (Tetranychus urticae) were transferred to each test plant ~4 ,, hours prior to treatment.
The test compounds were prepared for spraying at 1000 ~ ppm (p~rts per million) concentration by dissolvin~ it '. in a small amount of acetone and l~dding a ~uitable wett~ng agent, Typlc~lly, o.6 grams of chemical were dissolved (or suspended) in 10 ml o~ acetone, two drops of Triton~X100 (tradem~rk; octylphenoxy polyethoxy ethanol with 9-10 ~ole percent of polye~hylene oxide) wetting agent were ~dded and thls was ~uspended in 100 ml of water to make a 6000 ppm suspenslon. An aliquot was then ~urther diluted with dis- :
tilled water to 1000 ppm concentration of chemical.
The infested plants were sprayed wlth the dls~ :
persion using a small spray atomi2er to thoroughly drench the ~oliage. The plants were returned to the greenhouse where they were held for six days. After this period the plants were examined for adu~t li~e mites rem~ini~g on the lea~es~ On an estimation basis and in comp~rlson with the num~er o~ ing mites on the chec~ plants, the percent ]

control W8S determined.

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In this mite contact test, 2,3,5-triphenylthiophene produced 100% contact at 1000 ppm concentration.
In a similar test the known chemical 2,5-bis(phenyl-thio)-thiophene (T. Fujisawa et al., Tetr. Letters, No. 49, 5071 [1968], which is outside the invention, displayed miticidal activity, but was phytotoxic as evidenced by pucker-ing of new growth. The known chemical 3,4-diphenylthiophene (H. J. Backer and W. Stevens, Rec. trav. chim., 59, 423 [1940]), which is outside the invention, showed no miticidal activity.
The known miticide 2-(~-t-butylphenoxy)cyclohexyl-2-propynyl sulfite (Omite; trademark) was used at 80 ppm and 16 ppm for mite control comparisons in a similar test; the LD95 for this chemical ranges from 20 to 100 ppm depending on environmental factors such as light intensity, temperature and humidity.
Exam~ 2 Mite One-Day Residual Te6t Cotton, ~ S~æ~ hlrsutu~ L., ~ariety Stone-~ille-213, in the ~econd primary llea~ stage, grown in twel~e ounce cups under greenhouse condltions at 7O-75C, wa~ used:in this t~st.
One plant ~two primary leaves) in one pot was used for each replics.te; two replicates were used for e~ch concentra~ion of chemical te~ted.
The test compound was prepared by dissolving 50 mgs of chemical in one ~1 of acetone, adding one drop o~ .:
Emul~or 719~ a commercial sur~ ce-~ctive disper~lng agent (trademark; polyoxyethylated vegetable oll) and suspended in 5O ml o:E water ~or ~ t~oncentrat~on of 1000 ppm (parts per milllon). Aliquot~ were ~urther diluted with dis-tilled water to the concentration tested.

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The plants ~ere sprayed with the di~persions o~
the chemical, using a small ~pray atomiæer to th~roughly dr~nch the f~llage.
One day following treatment a circle of tree tangle-foot was placed on the upper surfaces of the treated leaves and adult mites were transferred into this con~inement. Counts of these mites were made im-mediately following transfer and again six days later.
Abbott~s formula was used to compensa~e for check mortallty. The ad~usted percent control w~s obtained by the following expression~ wherein A is the ad~usted control~ C is the ~ liYe mltes on check plants and T
ls the ~ live mites on treated plants:

C-T _ _ X 100 Dsta from the ~ite one-day residual te~t ~re shcwn in Table I.
_ble I

Mite One Day Residual Test of 2,3,5-Triphenylthi~phene ~ Control PPM PPM PPM

`; ' ~ ~' ` ' ~ 3 Example 3 This example illustrates a citrus rust mite test.
Grapefruit trees, of the variety Thompson Pink, were treated in this test conducted at Sanford, Florida. The trees were naturally infested with a population of the citrus rust mite, Phyllocoptruta oleivora, which is a pest that feeds on both foliage and fruit of citrus trees. Four replicate trees were treated with each chemical rate. Sprays were applied at lO0 lbs. pressure with a spray gun which was used to drench the foliage. In the counting procedure, twenty-five leaves were sampled on each tree, lO0 leaves per treatment. A one-square-inch area of each leaf was examined with a hand lens.
A density index number was recorded for each leaf examined as follows - O = no mites, l-l-2 mites, 2=3-6 mites, 3=7 or more mites. These index numbers were then totalled and divided by the number of leaves to provide an average density rating.
The percent reduction of citrus rust mite density over the untreated checks was then calculated by adaptation of Abbott's formula:

Density Rating Reduction = Check - Treated X lO0 Density rating of check Counts were made at intervals after treatment, as indicated in Tables II and III.
The results on Table II indicate that the compounds employed in this invention, namely 2,3,5-triphenylthiophene/
compares most favorably with a widely used commercial product where the long range control of citrus rust mites ls concerned.
Table III provides additional evidence that the compound employed in this invention is most suitable for the control of citrus rust mites. ~ `

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Percent Reduction of Citrus Rust Mite Density Using :~ 2,3,5-Triphenylthiophene Over the Untreated Check ., ' Rate PPM 10 Days Post-Treatment *10 leaves counted/rep. Each rep. equalled ~ .
~ a 12-inch branch tip isolated with Tanglefoot.

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The invention is remarkable for its ability to control the citrus rust mite on oranges, grapefruit and similar crops.

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Claims (4)

Div.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of controlling acarid or insect pests comprising contacting the acarid or insect pests with an acaricidal or insecticidal amount of 2,3,5-triphenylthiophene.

2. The method of Claim 1 in which the pests are mites located on plant life.

3. A miticidal or insecticidal composition comprising 2,3,5-triphenylthiophene in miticidally or insecticidally effective amount, in admixture with a carrier therefor.

CLAIM SUPPORTED BY SUPPLEMENTARY DISCLOSURE

4. The method of Claim 2 in which the mites are citrus rust mites.